Toothfish are also a species of deep water fish which live in the Southern Ocean and around the continent of Antarctica. These large fish feed on squid, prawns and other fish and are themselves preyed on by Sperm Whales, Elephant Seals, Colossal Squid and humans. These lucrative fish are the basis of a risky fishery which threatens the health of the most pristine ocean on the planet - the Ross Sea.